IT201900000145A1 - SHAFT-HUB CONNECTION SYSTEM WITH ANGULAR CLEARANCE FOR BIDIRECTIONAL TRANSMISSION OF THE DRIVE TORQUE. - Google Patents

Description

“SHAFT-HUB CONNECTION SYSTEM WITH ANGULAR CLEARANCE FOR BIDIRECTIONAL TRANSMISSION OF THE DRIVE TORQUE”.

DESCRIPTION

The present invention relates to a shaft-hub connection system with angular play for the bidirectional transmission of the drive torque.

Shaft-hub connection systems are known which allow bidirectional transmission of the drive torque in the two directions of rotation around the longitudinal axis of the shaft, but with a limited angular clearance between shaft and hub.

With particular, but not exclusive, reference to the agricultural machinery sector, these connection systems are typically used in cardan shafts for the transmission of the drive torque from the driving shaft of the power take-off of a tractor to the yielding shaft of an operating machine from operate. These systems, so-called "free rotation", allow to have a certain angle of relative free rotation between the ends of the cardan shaft, so as to facilitate its installation by compensating for any angular displacements between the driving shaft and the yielding shaft, whereas the coupling of these shafts with the relative cardan joints is generally of the splined or in any case prismatic type. When starting the tractor power take-off, regardless of the direction of rotation of the same, after having performed a limited angle of free rotation, these connection systems allow the transmission of the driving torque to the operating machine in both directions of rotation.

There are different types of connection systems for this kind of applications which essentially differ in the elements of the cardan shaft between which the components of the system are interposed.

In particular, connection systems of the type described above are known which are positioned in correspondence with the outer fork of one of the two end cardan joints, intended for use to be coupled to the driving shaft of the tractor or to the yielding shaft of the operating machine.

A solution of this kind is known, for example, from patent application GB2296308A which describes a connection system comprising a female sleeve element, which acts as a hub and is connected to an external fork of the cardan shaft, inside which it is supported in rotation around the relative longitudinal axis a cylindrical male element, which acts as a shaft and in use is able to be coupled to the driving shaft of the tractor or to the yielding shaft of the operating machine.

Between the shaft and the hub there are interposed a first and a second group of tabs, respectively, for the transmission of the driving torque in a first and second direction of rotation around the longitudinal axis. The tongues of the first and second group are movably housed in respective slots defined on the outer skirt of the shaft and are able to engage in corresponding abutment seats defined in the internal wall of the hub.

The orientation of the cross section of the abutment seats for the tabs of the first and second group with respect to the main axis is opposite.

Between each tongue and the bottom of the respective slot there are interposed elastic compression means acting on the tongue itself at a lateral end with respect to an ideal plane passing through the longitudinal axis of the shaft and the center line of the slot itself.

For the tongues of the first and second groups, the positioning of the respective elastic means inside the relative slots is opposite.

Each tab is therefore movable between a first and a second position with respect to the relative slot.

In the first position, the key is completely housed inside the respective groove, compressing the elastic means, so as not to interfere with the hub and to allow relative free rotation between shaft and hub itself.

In the second position, due to the thrust exerted by the elastic means, the tongue moves with respect to the aforementioned ideal plane, until it partially protrudes from the relative slot to engage in the corresponding abutment seat on the hub and allow the transmission of the torque in a first or in a second direction of rotation.

The system can therefore assume different configurations, including a free rotation configuration in which the tabs of the first and second group are in the first position to allow relative free rotation between shaft and hub, a first operating configuration in which the tabs of the first group are engaged in the respective abutment seats for the transmission of the drive torque in a first direction of rotation and the tabs of the second group are in the first position and a second operating configuration in which the tabs of the second group are engaged in the respective abutment seats for the transmission of the driving torque in a second direction of rotation and the tabs of the first group are in the first position.

These known types of connection systems are not free from drawbacks, including the fact that for the bidirectional transmission of the drive torque they need to provide, for each direction of rotation around the main axis, a dedicated group of tabs with a particular conformation and a particular positioning of the relative elastic means and a corresponding group of abutment seats of suitable conformation.

Such known systems therefore have a complex structure, with the need to prepare a considerable number of components which must be assembled according to particular operating methods, therefore they involve high production costs, as well as a not negligible risk of obtaining defective parts to be reworked.

Furthermore, the need to provide two distinct groups, one for each direction of rotation, of tabs with the relative slots and abutment seats, which must be distributed on the cross section of the system, entails the need to provide an adequate sizing of shaft and hub. as the drive torque to be transmitted varies, so that as the torque increases there is a considerable increase in the transverse dimensions of the system.

The aim of the present invention is to eliminate the aforementioned drawbacks of the prior art by devising a shaft-hub connection system with angular play for the bidirectional transmission of the drive torque which allows to reduce the number of components, to simplify the structure and to facilitate assembly operations, in order to contain production costs and reduce the risk of obtaining processing waste.

Within the scope of this technical task, another object of the present invention is to allow, with respect to known solutions, a reduction in the transversal dimensions for the same torque to be transmitted or to increase the torque transmitted for the same transversal dimensions.

A further object of the present invention is to be able to be easily incorporated in cardan transmission units for agricultural machines.

Another object of the present invention is to present a structure that is simple, relatively easy to implement in practice, safe in use and effective in operation, as well as having a relatively low cost.

This task and these purposes are all achieved by the present shaft-hub connection system with angular play for the bidirectional transmission of the drive torque comprising a shaft extending along a main axis, a hub equipped with a hole inside which said shaft is at least partially housed. and connection means with predefined angular play which are interposed between said hub and said shaft for the bidirectional transmission of the drive torque around said main axis and are able to alternatively assume at least one configuration of relative free rotation between shaft and hub around the axis main, a first operating configuration for transmitting the torque between shaft and hub in a first direction around the main axis and a second operating configuration for transmitting the torque between shaft and hub in a second direction, opposite to the first, around the axis itself , these configurations being angularly out of phase to each other around the main axis, characterized in that said connecting means comprise at least one functional group comprising a slot associated with the outer shell of said shaft in which a corresponding coupling member is movably housed which is able to alternatively assume a first position in which it is retracted inside said slot, a second position in which it is partially protruding with respect to it according to a first orientation and a third position in which it is partially protruding with respect to it according to a second orientation, elastic compression means interposed between said slot and said coupling member for moving the member itself from the first to the second or third position, a first and a second abutment seat of said coupling member, respectively in the second and third position which are internally associated with the said hub and are angularly out of phase around said main axis, in the pri but position the clutch member being completely housed inside the slot for maintaining the configuration of relative free rotation and in the second or third position the clutch member being partially protruding from the slot itself to engage, respectively, in the first seat in the first operating configuration or in the second seat in the second operating configuration.

Further characteristics and advantages of the present invention will become more evident from the detailed description of some preferred but not exclusive embodiments of a shaft-hub connection system with angular play for the bidirectional transmission of the drive torque, illustrated by way of example, but non-limiting, in the joined tables of drawings in which:

Figure 1 is a schematic cross-sectional view orthogonal to the main axis of a first embodiment of a shaft-hub connection system with angular play for the bidirectional transmission of the drive torque according to the invention, comprising a single functional group shown in the first operational configuration;

Figure 1a is an enlarged scale view of a portion of Figure 1 corresponding to the relative functional group;

Figures 2-4 are schematic cross-sectional views orthogonal to the main axis of a second embodiment of the system according to the invention comprising three functional groups represented, respectively, in the first operating configuration, in the free rotation configuration and in the second operating configuration;

Figure 5 is a schematic section view orthogonal to the main axis of a third embodiment of the system according to the invention, which consists of a variant of the second embodiment of Figures 2-4;

Figure 6 is a schematic section view orthogonal to the main axis of a fourth embodiment of the system according to the invention, comprising five functional groups represented in the first operating configuration;

figure 7 is a schematic axonometric view of a cardan shaft comprising the connection system according to the invention;

figure 8 is an enlarged and partially sectioned view of an end of the cardan shaft of figure 7 comprising the system according to the invention;

figure 9 is a schematic exploded axonometric view of the fork of figure 8, comprising a connection system according to the second embodiment of figures 2-4;

Figure 10 is a schematic exploded axonometric view of a variant of the fork of Figure 8, comprising a connection system according to the fourth embodiment of Figure 6;

Figure 11 is a schematic longitudinal section view of a further variant of the fork, comprising a connection system according to the third embodiment of Figure 5;

figure 12 is a schematic side view of an alternative embodiment of the fork comprising the system according to the invention;

Figure 13 is a schematic sectional view along the plane marked XIII-XIII of Figure 12.

With particular reference to these figures, the reference numeral 1 generally designates a shaft-hub connection system with angular play for the bidirectional transmission of the drive torque.

The expression “bidirectional transmission” means the possibility of transmitting drive torque in both directions of rotation around the rotation axis.

The system 1 comprises a shaft 2 extending along a main axis A. The shaft 2 can be provided with an axial hole 3 for connection to a driving or transferring element, not shown. It is not excluded that the shaft 2 may be solid and provide for a different coupling with the driving or transferring element.

The system 1 also comprises a hub 4 provided with a hole 5 inside which the shaft 2 is at least partially housed. The hub 4, in use, is able to be connected to a transferring or driving element, not shown.

The hole 5 extends along the main axis A and can be blind or passing through the hub 4.

The shaft 2 can be inserted passing through the hole 5, or with one end of it housed inside the hole itself.

The system 1 also comprises connection means 6 with predefined angular clearance which are interposed between the hub 4 and the shaft 2 for the bidirectional transmission of the drive torque around the main axis A.

Said connection means 6 are able to alternatively assume at least one configuration of relative free rotation between hub 4 and shaft 2 around the main axis, a first operating configuration for transmitting the torque between shaft 2 and hub 4 in a first direction around the main axis A and a second operating configuration for transmitting the torque between shaft 2 and hub 4 in a second direction, opposite to the first, around the axis itself, these configurations being angularly offset from each other around the main axis A.

The clockwise or anti-clockwise direction with respect to the figures in which the drive torque is transmitted around the main axis A in the first and second operating configuration depends, according to the specific application of the system 1, on which shaft 2 and hub 4 is connected to the driving element of the kinematic chain.

The connection means 6 comprise at least one functional group 7 comprising a slot 8 associated with the outer shell of the shaft 2 in which a corresponding coupling member 9 is movably housed, which is able to alternatively assume a first position in which it is retracted to the inside the slot 8, a second position in which it partially protrudes with respect to it according to a first orientation and a third position in which it partially protrudes with respect to it according to a second orientation, elastic compression means 10 interposed between the slot 8 and the coupling member 9 for moving the member itself from the first to the second or third position, a first and a second seat 11 and 12 for abutment of the coupling member 9, respectively in the second and third positions which are associated internally with the hole 5 of hub 4 and are angularly offset around the main axis A.

The seats 11 and 12 are arranged in correspondence with the same cross section with respect to the main axis of the hub 4, but in distinct angular positions with respect to this axis.

Preferably the slot 8 is directly obtained in the shaft 2 and the seats 11 and 12 are directly defined in the hub 4.

In the first position (Figure 3) the coupling member 9 is able to maintain the configuration of relative free rotation between shaft 2 and hub 4. In the second position (Figures 1,2,5,6) the coupling member 9 is adapted to engage in the first seat 11 in the first operative configuration for the transmission of the driving torque in the first direction around the main axis A.

In the third position (Figure 4) the clutch member 9 is able to engage in the second seat 12 in the second operating configuration for the transmission of the driving torque in the second direction around the main axis A.

The coupling member 9 comprises a first surface 13 facing towards the bottom of the slot 8 delimited in a longitudinal direction by two opposite edges 14 substantially parallel to the main axis A. The first surface 13 is preferably flat, but it is not excluded that it may be differently shaped.

Preferably, on at least one plane substantially orthogonal to the main axis, the elastic means 10 act on the coupling member 9 at least in correspondence with a median portion 13a of the first surface 13 comprised between the two opposite edges 14 and spaced from them.

The term "substantially" means unless the usual manufacturing or assembly tolerances.

Unlike known solutions, in which the elastic means act in correspondence with one of the end portions of the clutch member, according to the invention the elastic means 10 act, or in any case concentrate their thrust action, in correspondence with at least one median portion 13a of the first surface 13 of the clutch member 9 spaced from the edges 14.

Preferably the slot 8 has a plane of symmetry P passing through the main axis A.

In a preferred embodiment, in the first position of the coupling member 9, the elastic means 10 act, or in any case concentrate their action, on at least a median portion 13a of the first surface 13 of the member itself arranged in proximity to or in correspondence with of this plane of symmetry P.

Furthermore, the slot 8 comprises two sides 15 arranged symmetrically with respect to the plane P and the coupling member 9 comprises a first and a second face, respectively, 16 and 17 opposite each other, each facing a corresponding side 15 of the slot.

In the first operative configuration, the coupling member 9 in the second position is positioned with the first face 16 resting on the corresponding side 15 and the second face 17 detached from the corresponding side 15.

In the second operative configuration, the coupling member 9 in the third position is positioned with the first face 16 detached from the corresponding side 15 and the second face 17 resting on the corresponding side 15.

In a preferred embodiment the faces 16 and 17 are parallel to each other and the sides 15 diverge in the direction of away from the main axis A.

Furthermore, the coupling member 9 comprises a second surface 18, opposite the first surface 13, facing inside the hole 5. The surfaces 13 and 18 are interposed between the faces 16 and 17. The second surface 18 is preferably flat, but not it is excluded that it may be differently shaped.

With reference to a section plane substantially orthogonal to the main axis A, the section of the first seat 11 comprises at least an abutment portion of a portion of the second face 17 of the coupling member 9 in the second position for the transmission of the driving torque in the first direction around the main axis A in the first operating configuration, while the section of the second seat 12 comprises at least one abutment portion of a portion of the first face 16 of the clutch member 9 in the third position for the transmission of the driving torque in the second direction around the main axis A in the second operating configuration.

Preferably, the section of the first seat 11 comprises respective abutment portions of a portion of the second face 17 and of the second surface 18 of the coupling member 9 in the second position, while the section of the second seat 12 comprises respective abutment portions of a portion of the first face 16 and of the second surface 18 of the coupling member 9 in the third position.

However, it is not excluded that the portions of the seats 11 and 12 facing the second surface 18 of the coupling member 9, respectively, in the second and third positions, may be shaped and do not match the surface itself. The shape of the seats 11 and 12 is such as to facilitate engagement and disengagement of the coupling member 9 from the seats themselves as a function of the relative direction of rotation between shaft 2 and hub 4.

The coupling member 9 preferably comprises a parallelepiped-shaped body, of the type of a tongue.

Conveniently, the system 1 can provide two or more functional groups 7, each of which comprises a respective slot 8 for housing a corresponding coupling member 9, respective elastic means 10, respective first and second abutment seats 11 and 12. These functional groups 7 are angularly out of phase with each other around the main axis A. The functional groups 7 are preferably distributed with uniform angular pitch around the main axis A.

The displacement angle between the seats 11 and 12 of each functional group 7 defines the maximum angular play expected in the relative free rotation between shaft 2 and hub 4 before assuming the first or second operating configuration for transmitting the drive torque.

Figure 1 shows a first embodiment of the system 1 equipped with a single functional group 7.

In this case, a maximum angular clearance between shaft 2 and hub 4 is substantially equal to 60 °. The maximum angular play can be varied at will by modifying the relative angular position of the seats 11 and 12.

The system 1 is represented in the first operative configuration, with the coupling member in the second position.

The elastic means 10 comprise at least one helical compression spring partially inserted in a radial development recess 19 facing at the bottom of the slot 8. Along the longitudinal development of the shaft 2, as a function of the linear extension of the coupling member 9 , two or more helical springs 10 can be distributed and housed in respective recesses 19. Figures 2-4 show a second embodiment of the system 1 in which three functional groups 7 of the type described above are provided angularly offset by two, by two of 120 °.

In this case, a maximum angular play is provided between shaft 2 and hub 4 substantially equal to 60 °, depending on the angular offset of the seats 11 and 12 of each functional group 7. This angular play can be varied by modifying the angular offset between the seats 11 and 12 of each functional group 7, remaining however smaller than the angular pitch with which the functional groups 7 are distributed.

In figure 2 the system 1 is shown in the first operative configuration, with the three coupling members 9 in the second position and engaged in the respective first seats 11.

In figure 3 the system 1 is represented in one of the angular configurations of relative free rotation between shaft 2 and hub 4, with the three clutch members 9 in the first position, completely retracted inside the relative slots 8 to compress the corresponding elastic means 10.

In figure 4 the system 1 is shown in the second operating configuration, with the three coupling members 9 in the third position and engaged in the respective second seats 12.

Figure 5 shows a third embodiment of the system 1 which consists of a variant of the previous one. In this case, the elastic means 10 of each functional group 7 comprise a leaf spring housed on the bottom of the relative slot 8 and acting on a median portion 13a of the first surface 13 of the corresponding coupling member 9.

Figure 6 shows a fourth embodiment of the system 1 which provides five functional groups 7, of the type described above with helical springs 10 housed in respective recesses 19, angularly offset by two, at two of 72 °.

Also in this case, a maximum angular clearance between shaft 2 and hub 4 is substantially equal to 60 °.

Alternative embodiments are not excluded in which the elastic means 10 provide for the use of elements which can be compressed in an elastic manner other than helical or leaf springs, such as, for example, blocks made of elastically deformable plastic material.

It should be noted that the number of functional groups 7 also varies as a function of the value of the driving torque to be transmitted. In fact, as this value increases, it is appropriate to provide more functional groups 7 to distribute the load acting on the coupling members 9 in the first and second operating configurations.

The system 1 according to the invention allows, with the same transversal overall dimensions, to increase the value of the transmissible driving torque or, with the same driving torque to be transmitted, to reduce the transversal overall dimensions of the system with respect to known solutions.

In fact, the system 1 provides, for each functional group 7, a single clutch member 9 acting for the bidirectional transmission of the driving torque, while the known systems provide two groups of distinct tabs acting for the transmission of the torque in the first and second directions around to the main axis and therefore entail a greater increase in transverse dimensions as the torque value to be transmitted increases.

Typically, the system 1 can be incorporated in a conventional cardan transmission assembly 20 of the type comprising a generally telescopic transmission shaft 21, having opposite ends associated with respective cardan joints 22, each of which comprises a respective outer fork 23 associated with a coupling element 24 to a driving or yielding shaft, not shown.

The unit 20 is equipped with protection means 25 arranged externally to the transmission shaft 21 and to the cardan joints 22, not described in detail as they are of a known type.

In the field of agricultural machinery, for example, the unit 20 is usually interposed between the driving shaft of the power take-off of a tractor and the yielding shaft of an operating machine to be driven. The presence of the system 1 incorporated in the unit 20 allows its installation to be facilitated since, thanks to the angular play allowed between shaft 2 and hub 4, it is possible to compensate for initial angular displacements of the driving and following shafts.

The system 1 can be interposed between one of the external forks 23 and the corresponding coupling element 24.

It is not excluded that the system 1 may be incorporated in the unit 20 in a different position, such as for example between the internal fork of one of the two universal joints 22 and the corresponding end of the transmission shaft 21.

This external fork 23 is equipped with a plate 26 from which two tines 27 project axially on one side and, on the opposite side, a sleeve 28 defining the hub 4 of the system 1. Inside the sleeve 28 = 4 is housed axially the coupling element 24 defining the shaft 2 of the system 1.

The coupling element 24 = 2 generally has the axial hole 3 having a grooved or in any case polygonal section to obtain a prismatic coupling with the driving or yielding shaft.

Connection means 6 of the type described above are interposed between the sleeve 28 = 4 and the coupling element 24 = 2.

In this way the coupling element 24 = 2 can perform a certain angle of free rotation around the main axis A with respect to the sleeve 28 = 4 and to the other elements making up the group 20 to compensate for any angular displacements of the driving or yielding shaft. to which it must be connected.

Preferably the system 1 is provided at the outer fork 23 of the cardan joint 22 intended to be coupled, in use, to the yielding shaft. However, it is not excluded that the system 1 may be incorporated in the outer fork 23 of the cardan joint 22 intended to be coupled, in use, to the driving shaft.

In the following figures, the reference number 30 indicates a system of axial retaining rings for the components of the system 1.

Figures 8 and 9 show an external fork 23 in which a system 1 is incorporated according to the second embodiment described above with reference to Figures 2-4, that is, equipped with three functional groups 7 with helical springs 10.

Figure 10 shows a variant of the previous outer fork 23 in which a system 1 is incorporated according to the fourth embodiment described above with reference to Figure 6, that is, equipped with five functional groups 7 with helical springs 10.

Figure 11 shows a further variant of the outer fork 23 in which a system 1 is incorporated according to the third embodiment described above with reference to Figure 5, or equipped with three functional groups 7 with leaf springs 10.

Finally, Figures 12 and 13 show an alternative embodiment of the outer fork 23 which incorporates, in addition to the system 1 according to the invention, a clutch unit 29 for limiting the transmitted torque, not described in detail as it is of the type known to the person skilled in the art. In addition to or replacing the friction assembly 29, there could be a different torque limiting system of a known type, such as an automatic limiter, with pawls or with shear bolt.

In practice it has been found that the described invention achieves the proposed aims and in particular it is emphasized that the system according to the invention allows to reduce the number of components used, to simplify their structure and not to require particular assembly methods. , simplifying the manufacturing and assembly cycle, reducing the risk of obtaining defective parts and reducing overall production costs.

Furthermore, since the clutch members according to the invention are active for the bidirectional transmission of the driving torque, the present connection system allows to reduce the transversal dimensions for the same driving torque to be transmitted, or to increase the value of the torque that can be transmitted to equal transverse dimensions. In fact, with the same external diameter of the shaft and the internal diameter of the hub, it is possible to distribute a greater number of clutch members simultaneously engaged in the first or second operating configuration with respect to known solutions which provide distinct groups of active keys for the transmission of the couple one way or the other.

The system according to the invention can also be easily incorporated in transmission units of the type of cardan shafts for agricultural machines.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby departing from the scope of the protection of the following claims.

Claims (11)

CLAIMS 1) Shaft-hub connection system (1) with angular play for bidirectional transmission of the drive torque including a shaft (2) developing along a main axis (A), a hub (4) provided with a hole (5) inside which said shaft (2) is at least partially housed e connection means (6) with predefined angular clearance which are interposed between said hub (4) and said shaft (2) for the bidirectional transmission of the drive torque around said main axis (A) and are able to alternatively assume at least one configuration of free relative rotation between shaft (2) and hub (4) around the main axis (A), a first operational configuration of torque transmission between shaft (2) and hub (4) in a first direction around the main axis ( A) and a second operational configuration for transmitting the torque between shaft (2) and hub (4) in a second direction, opposite to the first, around the axis itself, these configurations being angularly offset from each other around the main axis (A ), characterized in that said connection means (6) comprise at least one functional group (7) comprising a groove (8) associated with the outer shell of said shaft (2) in which a corresponding coupling member (9) is movably housed adapted to alternatively assume a first position in which it is withdrawn inside said groove (8), a second position in which it is partially protruding with respect to it according to a first orientation and a third position in which it is partially protruding with respect to it according to a second orientation, elastic compression means (10) interposed between said groove (8) and said coupling member (9) for the movement of said member from the first to the second or third position, a first and a second seat (11, 12) for abutment of said clutch member (9), respectively in the second and third positions which are associated internally with the hole (5) of said hub (4) and are angularly out of phase around said axis. incipal (A), in the first position the coupling member (9) being completely housed inside the groove (8) to maintain the configuration of relative free rotation and in the second or third position the coupling member (9 ) being partially protruding from the slot itself to engage, respectively, in the first seat (11) in the first operating configuration or in the second seat (12) in the second operating configuration. 2) System (1), according to claim 1, characterized in that said clutch member (9) comprises a first surface (13) facing the bottom of said groove (8) delimited in the longitudinal direction by two edges (14) opposed substantially parallel to said main axis (A) and that, on at least a plane substantially orthogonal to the main axis itself, said elastic means (10) act on said clutch member (9) at least in correspondence with a median portion (13a) of said first surface (13) comprised between said two opposite edges (14) and spaced from them. 3) System (1), according to claim 1, characterized in that said slot (8) has a plane of symmetry (P) passing through said main axis (A) and that said elastic means (10) act on said member of coupling (9) in the first position at least in proximity to said plane of symmetry (P). 4) System (1), according to claim 1, characterized in that said groove (8) has a plane of symmetry (P) passing through said main axis (A) and that said elastic means (10) act on said member of coupling (9) in the first position at least in correspondence with said plane of symmetry (P). 5) System (1), according to claim 1, characterized in that said groove (8) has a plane of symmetry (P) passing through said main axis (A) and comprises two sides (15) opposite each other with respect to the plane itself and that said clutch member (9) comprises a first and a second face (16,17) opposite each other, each facing a corresponding side (15) of the slot itself, in the first or second operating configuration, respectively, the first face (16) or the second face (17) of the coupling member (9) being positioned against the corresponding side (15) of the slot (8) and the second face (17) or the first face (16) being detached from the corresponding side (15) of the quarry itself. 6) System (1), according to claim 5, characterized by the fact that said first and second faces (16,17) are substantially parallel to each other and that said sides (15) are divergent from each other in the direction of moving away from said main axis (TO). 7) System (1), according to claim 2 and 5 or 6, characterized in that said clutch member (9) comprises a second surface (18) opposite said first surface (13) and facing towards said hub (4) , the first and second surfaces (13,18) being interposed between said first and second faces (16,17). 8) System (1), according to claim 7, characterized in that on a plane substantially orthogonal to said main axis (A), the sections of said first and second seat (11,12) comprise at least a respective supporting portion of a portion of the second face (17) of said clutch member (9) in the first operating configuration and of a portion of the first face (16) of the member itself in the second operating configuration. 9) System (1), according to one or more of the preceding claims, characterized in that said coupling member (9) comprises a parallelepiped-shaped body. 10) System (1), according to one or more of the preceding claims, characterized in that it comprises at least two of said functional groups (7) each of which comprises a respective slot (8) for housing a corresponding coupling member (9) , respective elastic means (10), respective first and second abutment seats (11,12), the functional groups (7) being angularly offset from each other around the main axis (A). 11) Cardan transmission assembly (20) comprising a transmission shaft (21) having opposite ends associated with respective cardan joints (22), each of which comprises a respective outer fork (23) associated with a coupling element (24) to a driving or yielding shaft, characterized in that it comprises a connection system (1) according to one or more of claims 1-10 interposed between one of said external forks (23) and the corresponding coupling element (24), said hub (4) and said shaft (2) being associated, respectively, with said outer fork (23) and said coupling element (24).